Packet based networks comprise a plurality of routers interconnected through communication links. Data transmitted in packet based networks are encapsulated in packets which each contain an address of a destination of the packet. Each router forwards packets it receives toward the respective destinations of the packets. Packet based networks are used to provide many services, including multimedia streaming, data broadcasting and both telephone and fax transmission.
Cellular telephone networks provide communication channels to mobile stations, which are not confined to a specific location. The mobile stations are serviced by base stations which wirelessly transmit signals to the mobile stations located in their vicinity, referred to as a cell. The network connecting the base stations to other communication networks is referred to as a terrestrial network. The cellular telephone networks provide data services using packet based protocols, such as the General Packet Radio Service (GPRS) protocol. According to the GPRS protocol, a mobile station (MS), which requires a data session, registers with a serving GPRS support node (SGSN). Thereafter, the MS generates a context request which initiates a context assignment procedure in which the MS is associated with a packet based address of an external packet based network.
In some cases, mobile stations subscribe to streaming content, such as video content, provided in packets by a streaming server. Where multiple mobile stations within the same cell subscribe for the same stream, the stream is delivered to each of the mobile stations separately, in a manner wasteful in bandwidth.
U.S. Pat. No. 5,887,252 to Noneman, the disclosure of which is entirely incorporated herein by reference, describes using multicast transmission over CDMA cellular networks.
U.S. patent publication 2004/0266440 to Fuchs et al., titled “Multicast Transmission in Packet Based Cellular Networks”, the disclosure of which is entirely incorporated herein by reference, describes a cellular network in which requests for streaming channels are intercepted and the streaming content to all the mobile stations in a single cell are provided on a channel of a virtual subscriber, to which all the mobile stations are instructed to listen.
Due to their complexity, multicast procedures have not been widely implemented.
PCT publication 2007/131296 to Williams et al., titled: “Redundant Media Packet Streams”, the disclosure of which is entirely incorporated herein by reference, describes use of redundant streams for backup purposes and for switching between the streams when there is a problem with one of the streams.
US patent publication 2006/0262851 to Bafkan et al., titled: “Method and system for Efficient Transmission of Communication Traffic” and U.S. Pat. No. 6,622,019 to Shalem et al., titled: “Increasing Channel Capacity in Fixed Cellular Networks”, the disclosures of both of which are entirely incorporated herein by reference, describe methods of reducing bandwidth utilization in cellular networks.